the energy required to remove an electron from a gaseous atom
as you go across the periodic table, energy increases
as you go down the periodic table ionization energy decreases

electronegativity

the tendency for an atom to attract electrons to itself when it is chemically combined with another element
as you go across, increases
as you go down, decreases

shielding

across, constant
down, increase

nuclear charge

the total charge of all the protons in the nucleus, it has the same value as the atomic number
across, increases
down, increases

valence electrons

amount of electrons in the last energy level. Valence electrons are important in determining how an element reacts chemically with other elements: The fewer valence electrons an atom holds, the less stable it becomes and the more likely it is to react

-For molecules with only 2 elements, arrange the atoms symmetrically
-“COOH” is a carboxylic acid (both O’s bond to the C and the H goes on one of the O’s)
Hydrogen and halogens cannot go in the middle
Write the remaining atoms in the order they appear in the formula
Write the hydrogen and halogen atoms around the element they are written next to in the formula

VSPER theory

a theory that predicts molecular shapes based on the idea that pairs of valence electrons surrounding an atom repel each other